8v92's turbo overheat at open throttle, help

[Thanasi]

yes, however, both engines are doing it you think thermostats failed on both engines at the same time

Must be some little buggers growing just inside the intakes. They love the hot soup water this time of year.

I've wasted 4 months waiting on mechanics and to get the boat pulled. Mechanics I've sent biz to in leaner times don't bother to show. My friend at MarineMax wouldn't commit to a day to pull her. Frustrating.

I happened to call Diversified Yacht Serv in Ft Myers Beach. The guy set a hard appt. to have the boat pulled in early Nov. and and set another for a mechanic to come this week. Then, he sent a new diver who's great. In a few weeks, I'll finally be able to get a proper survey and tell Geico to give me a competitive rate or get lost.

One day, I just had a thermostat start sticking halfway open. Things like that happen. If you haven't changed them in a while, now might be a good time to try that. I didn't know that was the issue until I put them in a pan of hot water and watched as one failed to open fully.

[Captain Ralph]

Do you have 1 or 2 thermostats per head?
I can not see how thermostats can fail at the same time on both engines.
However, fouling can easily happen at the same time.

Remote oil coolers clog up quicker that the ole Detroit cast heat exchanger.

If you have original raw water hoses, Probably time to replace them any way. You would be amazed what can grow in those hoses. I have witnessed the inside laminate deteriorate and suck in on old hoses also.

[Thanasi]

Do you have 1 or 2 thermostats per head?
I can not see how thermostats can fail at the same time on both engines.
However, fouling can easily happen at the same time.

Remote oil coolers clog up quicker that the ole Detroit cast heat exchanger.

If you have original raw water hoses, Probably time to replace them any way. You would be amazed what can grow in those hoses. I have witnessed the inside laminate deteriorate and suck in on old hoses also.

so are you suggesting that the t-stats may be fouled? so check them anyway? are there 2 or 4 per engine? also the remote oil coolers are you reffering to the ones on the side of the block that also cool the fuel. Thank you

[rsmith]

Check the coolant concentration. In warmer waters Detroit recommends straight water with antirust additive.

[Captain Ralph]

so are you suggesting that the t-stats may be fouled? so check them anyway? are there 2 or 4 per engine?

No, I am suggesting there is not a thermostat issue and leave them alone.
Both engines having thermostat issues at the same time would be near un-heard of.

I also asked (from curiosity) how many thermostats your V-92s have. My 12V71s have 4, 2 per head.

Barnacle fouling in the raw water system, IMO is probably where your issue is. This CAN affect both engines at the same time.

[Captain Ralph]

the remote oil coolers are you reffering to the ones on the side of the block that also cool the fuel. Thank you

This may indicate that you have the TA engines. At the intake of this heat exchanger, rear end facing to the raw water pump, is where I would hunt for obstructions.

[Hat52MY]

It does not take much growth on the raw water side to see temps rise at full power and run fine at hull speeds. Run barnacle buster through the raw water system, from the impeller to the exhaust discharge, in both directions. There are an number of posts on the forum on how to do this. I suspect, you will see a drop in temps at full throttle once cleaned. I do this once every 2-3 years as normal maintenance. Best of luck!

[kelpy]

I would also suspect intake water circuit fouling if the problem is being experienced on both engines at the same time. It could also be dirty aftercoolers if there has been a recent engine room exhaust leak. It can't be dirty intercoolers because 92 series engines don't have them. It cant be fouled oil coolers because the coolers use engine coolant, not raw water,

[Captain Ralph]

It can't be dirty intercoolers because 92 series engines don't have them.

Intercoolers, the air coolers mounted between the turbo and blower are raw water cooled.
After coolers, are coolant / HE cooled and mounted under the blowers in the V valley.

92s come in intercooled (TI), aftercooled (TA) and some both (TIA)..

[kelpy]

Nope. Not from the factory. N, TA and TTA only for marine use. Perhaps you are getting the 92 series confused with the 71 series of engines.